The deal with social security is, that as long as you were married for 10 years, when the time comes to collect social security, you can choose whichever is the larger - SS based on your own earnings, or spousal SS (which is 50% of the his benefit or 75% if he's died). Also, if you were married for ten years, if he dies, you can collect a widow's benefit at age 60. So it's valuable to make sure you were married for ten years.

(My friend is widowed, and her husband was married twice before her. This doesn't affect her benefit - she and both previous wives - who were also married to him for ten years - all collect social security widows benefits based on his earnings. It's not reduced even if he marries again.)

Things you will want to ask the lawyer about:
1) His credit card debt. If this was mutual debt (used to buy things for both of you during the marriage) he might be able to hold you to paying half of it. If it's all debt that he incurred after you "split", or that he spent on OW, or you paid off a similar amount of "joint " debt on your card but he neglected to do so on yours, then you have a good case for him being responsible for all of that debt. The fact that you have separate cards would work in your favor I would think.

2) Alimony - usually for half the duration of the marriage, assuming there is a disparity between your income and his. This would be 5 years in your case. If you usually make as much as he does but are just temporarily unemployed this might be different.
3) Things to consider with the alimony:
If he dies before it's all paid, how are you protected? I carried (and paid for) a life insurance policy on my ex during the years he paid me alimony.

Consider a lump sum settlement. I actually wish I had been able to get a lump sum instead of the 10 years of alimony that I got, because with every check ex sent me he got more and more resentful and stuck me with every extra expense for our adult children just to get back at me (and ruined his relationships with the kids in the process). A lump sum is usually a bit less than what the total alimony would be (because it assumes you can invest and grow that money over the 5 years). That could make if attractive to him as it looks like less, but it also requires him to come up with a lump sum which he might not be able to do.Lump sum removes uncertainty (if he dies after you still have your money, and you don't have to worry abut late checks etc.). Lump sum might also allow you to make different choices about your future.

Tax consequences of alimony. The tax laws in the US have changed. Alimony is now taxable to him and not taxable income to you. Neither of you pay taxes on a lump sum distribution. Here's a simple mathematical model of how this might work out:
Let's say you receive alimony of 1,000 a month for five years. If his top tax bracket is 20%, he has to earn $1,250 to pay you that $1,000 (he pays the remaining $250 in taxes. You pay no taxes on that $1,000.
If, on the other hand, you negotiate a lump sum settlement: $1,000/mo x 5 years = $60,000. But remember, you can invest that money, so usually the lump sum is discounted. Let's say the assumption is that you could earn 4% above inflation by investing that money, the lump sum would be discounted to $50,000 but in five years you would have $60,000 if you left that invested. It might sound like taking the $1,000 a month payments would be better for you, especially since you have to use some of that money for living expenses. However, would having the lump sum enable you to make some other changes that would be useful? Down payment on a condo that would reduce your living expenses? Enable you to fund training or a vehicle that would allow you to earn more money? Even if he gives you $60,000 lump sum, he saves $15,000 in taxes (but loses maybe $5,000 in potential investment earnings).

Another alternative is to negotiate a bigger part of his retirement. If he can't come up with the cash but will give you an extra $50 or $60 K of his IRA or 401K, it doesn't help you in the short term but may set you up for a better retirement. (although there are ways to take money out of an ira before age 59 1/2 without tax penalty, it's complicated).

Otherwise, you just split those 50:50 and transfer yours into your own IRA to avoid tax consequences now.

If he has an actual pension, usually you really want to hold onto your share (which is divided by a procedure called QDRO, which will calculate how much was earned during the years you were married and split that in half roughly). It's better if it's the type that increases with inflation. My ex's does not so even though the initial benefit I get is generous, it decreases in value over time due to inflation. Usually you're better off if you hold onto your QDRO share rather than let him buy you out of the pension; as women often haven't built up enough retirement savings themselves.