Break Up & Divorce

Is being a "security blanket" for your ex normal?

I dated a guy for a couple of years 4 years ago now. It was a very intense relationship and it ended when I couldn't forgive him for getting close to his ex again. He didn't cheat, but he confessed he came close, and they continued to have contact. The break up was messy, I continued to sleep with him after even though I wanted a relationship with him still, he didn't want that. We eventually broke contact for a year, I had a relationship with someone else. When that ended I contacted him again, and we were pen pals while he lived abroad for 6 months for school. When he moved back we hung out and chatted often, culminating in us sleeping together again. When I found out that he still didn't want a commitment we stopped talking again. This time for almost 2 years. We reconnected again, this time not sleeping together, and he wanted to commit this time. I was too scared and said no. Months go by and a few times we have slept together again, each time me ending the fling because I'm hurt. Most recently he told me that the reason he does this is because I am the closest he has ever been with intimately, so it's a comfort thing. I freaked out as per usual and accused him of just continually using me for sex and cut ties. A couple of my guy friends tried to explain to me that we are each others security blankets. Is this a thing? And isn't it unhealthy? Have I over-reacted? Is it normal for us to have someone from our past that we turn to when times get hard for intimacy and to feel safe? Does this mean I can stop beating myself up for being such a fool? Or did I do the right thing by cutting ties with someone I know cares about me, but hurts me repeatedly with his rejection? Help! I am so torn.
Is being a "security blanket" for your ex normal?
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