So, I understand how you feel about your ex's new BF and the kids gifts. I am going to play devil's advocate and not really say the guy is bad. Yeah, he dated someone who's divorce isn't final. I have my opinion on that. I don't think it is something that lowers someone's moral character. Many people do it knowing it's a matter of signing a document.
Now, really, I wouldn't date a guy who was separated because I feel like they really need some time being on their own (hence why I was hesitant to even date a newly divorced person). I dated when I was still technically married. My ex was deep in an R just waiting for the papers to be signed to move her in and propose to her. I knew our marriage was very over. But my fault was I knew I wasn't ready to date. I didn't feel like I was violating any sacred vows.
But your wife was wrong to send the kids in the gifts from her BF. Unless the kids insisted on wearing them. It just stinks all around. My daughter was flipping through pictures on her phone with me and there were selfies of all 3 of them in her bed. It still stings, after all these years. OWW has her FB cover photo of her and my D, her phone screen saver of the 3 of them. It will always sting. I am sorry someone else has to feel that pain. Today is actually the day they celebrate their "dating" anniversary (which I found out about only when they were engaged). I was 30 weeks pregnant in a high risk pregnancy living an hour away from my hospital and he never came home after work one night. I found out why one night when he left his email open on our computer when he used it to pull up a coupon to take our D out to dinner one night). I looked, and there was pictures from 7-20-07 of them at a baseball game with their arms around each other while I sat at home (actually drove 45 min to the train station to see fi his car was still there at 2am) thinking the father of my child was dead. He came home at 5am, mad at ME for being mad at him. Oh, both of their email address have that date in it.
Now for your date. I hope you had fun. I was a lot like you when I began dating, putting so much pressure on it. After a while, the nervousness went away, and I realized it was committed to nothing and when I took the pressure away from myself of having to "catch up" to ex, it got easier.
I wonder sometimes if my ex thinks in his head "10 years, and she still is single, no one must want her, I was right". I couldn't wait to show him I am lovable and someone could love me for me. It never happened. But I look at him, and while I think he may have gotten what he wants, he still seems miserable all the time. I am sure there are many other men I could have been miserable with. I was just sick of being miserable! Someone has got to add a special quality to my life. ANd if that takes 20 years, so be it, I guess.
Didn't mean to make that about me, but I can empathize. I have been there. There will be a lovely very lucky lady in your life one day. Don't rush it, and don't put pressure on it. ANd think outside the box a little. See, when my ex left, the first guy I dated was the total opposite in looks. I WANTED that. My ex was 5'7 and thin. This guy was 6'3" and an MMA fighter. (lord he was hot). But I always thought I could only be attracted to short thin guys..... turns out, I can be attracted to short or tall, muscular, chubby, white, back, Hispanic, Asian...……. who knew?!